In 2005, Wikipedia surpassed Encarta as the Internet's most popular reference site. Wikipedia calls itself "the free encyclopedia that anyone can edit," and it has grown rapidly since its founding in 2001. As an educator and parent, Greenstein finds himself struggling to come to terms with the economics of Wikipedia, which have shaped a resource that is at times very good, but occasionally poor. The inconsistency is a result of Wikipedia's long tail, a characteristic that requires some explanation. And thereby hangs a tale.